> - Either I use a "r" constraint and let gcc produce the instructions, > that I need to assume to have correct size so I can align their > immediate values (therefore, taking the offset from the end of the > instruction will not help). Here, if gas changes its behavior > dramatically for a given immediate value size, it will break.
I wouldn't expect it to do that, but you could perhaps add a self test somewhere to check for it. > > - Second choice is to stick to a particular register, choosing the one > with the less side-effect, and encoding the instruction ourselves. I > start to think that this second solution might be safer, even though > we wouldn't let the compiler select the register which has the less > impact by itself. Such effects caused occassional bugs in the alternative() implementation which requires a maximum size for the replacement. But in this case it should be safe enough to trust gas stability. -Andi - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
